Method and Apparatus for Performing Login by Mobile Station in Wireless Communication System

1. A method for performing login by a Mobile Station (MS) within an Internet Protocol Multimedia Subsystem (IMS) network in a wireless communication system, comprising: performing temporary login to an IMS server by using a subscriber identity (ID) as a virtual Private Identity (PRID); receiving, from the IMS server, information about at least one first PRID previously registered for the subscriber ID; determining whether the at least one first PRID is identical to at least one second PRID managed by the MS; and if the at least one first PRID is identical to the at least one second PRID, performing logoff for the temporary login, and performing login to the IMS server using a third PRID, as one of the at least one second PRID, to log off another MS that is logged on using the third PRID.

2. The method of claim 1 , wherein performing logoff for the temporary login comprises: performing the logoff for the temporary login by transmitting a logoff request for the subscriber ID to the IMS server.

3. The method of claim 1 , further comprising: if the at least one PRID is different from the at least one second PRID, determining whether there is at least one PRID unregistered in the IMS server among the at least one second PRID; and if there is the at least one unregistered PRID, performing logoff for the temporary login, and performing login to the IMS server using a fourth PRID as one of the at least one unregistered PRID.

4. The method of claim 1 , further comprising: updating status information of the at least one second PRID as the third PRID is used for login; and transmitting the updated status information to the IMS server such that the updated status information is transmitted to other MSs that use the subscriber ID.

5. The method of claim 1 , further comprising: transmitting a logoff request for the subscriber ID to the IMS server, if there is no the at least one first PRID; and performing login to the IMS server using one of the at least one second PRIDs that are not registered in the IMS server.

6. A Mobile Station (MS) for performing login within an Internet Protocol Multimedia Subsystem (IMS) network in a wireless communication system, comprising: a transceiver configured to communicate with an IMS server, and receive, from the IMS server, information about at least one first Private Identity (PRID) previously registered for the subscriber identity (ID); a memory configured to store a subscriber identity (ID), the at least one first PRID and at least one second PRID being managed by the MS; and a controller configured to: perform a temporary login to the IMS server by using the subscriber ID as a virtual PRID, determine whether the at least one first PRID is identical to at least one second PRID, and if the at least one first PRID is identical to the at least one second PRID, performing logoff for the temporary login, and perform login to the IMS server using a third PRID, as one of the at least one second PRID, to log off another MS that is logged on using the third PRID.

7. The MS of claim 6 , wherein the controller performs the logoff for the temporary login by transmitting a logoff request for the subscriber ID to the IMS server through the transceiver.

8. The MS of claim 6 , wherein the controller, if the at least one PRID is different from the at least one second PRID, determines whether there is at least one PRID unregistered in the IMS server among the at least one second PRID, and if there is the at least one unregistered PRID, performing logoff for the temporary login, performs login to the IMS server using a fourth PRID as one of the at least one unregistered PRID.

9. The MS of claim 6 , wherein the controller updates status information of the at least one second PRID as the third PRID is used for login, and transmits the updated status information to the IMS server through the transceiver such that the updated status information is transmitted to other MSs that use the subscriber ID.

10. The MS of claim 6 , wherein the controller transmits a logoff request for the subscriber ID to the IMS server if there is no the at least one first PRID, and performs login to the IMS server using one of at least one second PRIDs that are not registered in the IMS server.